Hi! I receive an error when I try to persist an entity bean. I have a bean (A) which relates to another bean (B). This relation is annotated as @ManyToOne(cascade = CascadeType.ALL) and @JoinColumn(nullable = false) The enity bean (B) has only one property beside the autogenerated id (Long) which its name (b.getName()). This property is annotated with @Column(nullable = false, unique = true). I use annotations over the fields of the properties. When I persist/merge these entities I get javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist: a.package.B | The methods which tries to persist the entities are: | public Long saveOrUpdate(A a) { | B b = a.getB(); | b.setId(saveOrUpdate(b)); | entityManager.flush(); | | // If b is persisted before, the persisting gives an exception | // I have actually never tried the merge option as a.getId() is null... | | if (a.getId() != null) { | entityManager.merge(a); | | return a.getId(); | } | | entityManager.persist(a); | | return a.getId(); | } | | public Long saveOrUpdate(B b) { | B persistedB = get(b.getName()); | | if (persistedB != null) { | return persistedB.getId(); | } | | entityManager.persist(b); | | return b.getId(); | } | Since B only have one property (name) and this is unique, my saveOrUpdate method of B only return the id of an allready saved instance. Therefore I use this id on B.setId(Long id) when the method is called. If B has not been persisted before it works as intended, but if the instance of B is located in the database, then the exception is thrown when I try to persist A... When A is persisted (even though there is a merge option in the code, every time I use this code, I persist a new instance of A - a.getId() == null - which may have an allready persisted instance of B) this exception is thrown even if the correct id is located in the instance of B which is tried to be persisted with A. Please help me with this exception. I thought a detached entity did not have a valid primary key (b.getId()), but this is not the case in this situation. I am growing frustrated... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3972588#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...